Soo, I've been somewhat on track this week, on my worst day I ate 100 cals over maintenance but I've gained 3 lbs! It's not salt, I've been watching that like a hawk....I'm thinking maybe it's humidity? The humid ex has been at 80 or above for the past 3 days and it's been exceedingly hot, also I've noticed bloating around my stomach....could I just be retaining water due to the heat/humidity?

It's driving me CRAZY!

I swell so bad when it's hot. That could very well be it! Maybe it's the weather, maybe its some ingredient in some food that you're not fully aware of, or some other phantom influence. I'm sure whatever it is, that 3 pounds will come right off.

Trust in science.

Calories matter.

Don't panic. Your body is an amazing thing, and it does all kinds of bizarro stuff to protect itself. Like John said, trust the science, and trust your body.

My general approach is not to worry about weird numbers on the scale until they're consistent for more than a week.

You could also check your scale battery

Heat, humidity, some random food that causes you to retain water, hormones, extra food in you intestines. Who knows what causes those annoying day to day fluctuations. Watch the week to week and month to month weight trend and don't worry too much about the day to day fluctuations. As long as you're honest with yourself and you're not getting too many calories, you're not gaining fat.